Crystal structure of KBe 2 BO 3 F 2

✍ Scribed by Mei, L.; Huang, X.; Wang, Y.; Wu, Q.; Wu, B.; Chen, C.

• Book ID: 120370226
• Publisher: Oldenbourg Wissenschaftsverlag
• Year: 1995
• Tongue: English
• Weight: 431 KB
• Volume: 210
• Category: Article
• ISSN: 2194-4946
• DOI: 10.1524/zkri.1995.210.2.93

✦ Synopsis

Abstract

Potassium beryllium borate fluoride, KBe~2~ · BO~3~F~2~, is rhombohedral (hexagonal axes) R__32 (No.155), a = b = 4.427(4) Å, c = 18.744(9) Å, V = 318.3(4) Å^3^, M = 153.93, D
~m~ = 2.40g · cm^−3^, D
~x~ = 2.41 g · cm^−3^ for Z = 3, F(000) = 222, μ = 11.84 cm^−1^, T = 296 K. The crystal structure has been determined by single crystal X-ray diffraction and final R value for 260 unique reflections with I > 3__σ(I) is 3.1%. The results reveal a new type of complex polyanions. All B atoms are planar triangularly coordinated while all Be atoms are tetrahedrally coordinated. The feature of the borate framework is infinite sheets [Be~2~BO~3~F~2~] which may be described in terms of six-membered rings of [Be~2~BO~6~F~2~] having Be–O and B–O edges in common. The nonlinear optical(NLO) properties of this compound are also discussed here and the [BO~3~]^3−^ anionic groups are principally responsible for the second harmonic generation (SHG) effect.